There were 12 colors available in 1950 as Options 234-235 with corresponding body stripes. Two-tone combinations or special colors were available only as special zone orders. Since there was no tag defining this color really anything goes now days, no one can say it didn't come that way as there is no way of knowing unless your truck has the original dealer order.
Below is the zone form for special orders, colors, etc.
https://www.flickr.com/photos/advance-design_parts_co/14932234635/in/album-72157631872034068/
Here is the salesman order book referencing two-tone color requests to the zone office.
https://www.flickr.com/photos/advance-design_parts_co/8335509814/in/album-72157631872034068/
Original color options by name are located in the Salesman Data Book shown here (1949 book with updates for 1950).
https://www.flickr.com/photos/advance-design_parts_co/11615644555/in/album-72157631872034068/
https://www.flickr.com/photos/advance-design_parts_co/11615858693/in/album-72157631872034068/

1950 Chevrolet 3/4-Ton 3600
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